Description of Work The goal of the proposed research is to understand the effects of ethanol exposure on neural systems responsible for the control of goal-directed actions and habit formation. Ethanol addiction is associated with a wide range of behavioral and cognitive deficits. While much progress has been made on the pharmacological targets mediating ethanol action on the brain, little is known about the adaptations resulting from ethanol addiction at the level of neural systems. So far, the majority of research on the effects of ethanol on goal-directed behavior has focused on alcohol self-administration paradigms. Rather neglected is the question of how ethanol affects the neural systems underlying normal reward-guided behavior. To understand the neuroadapative mechanisms responsible for the addictive properties of ethanol, we must first understand how it affects the normal mechanisms underlying reward-guided behavior in general. More specifically, little research has been conducted on the effects of ethanol on the striatum, a key structure in the control of voluntary behavior that has been implicated in habit formation and addiction as a result of recent research. Consequently, not much is known about how ethanol can change striatum-dependent learning and behavior. In this proposal it is hypothesized that exposure to ethanol (using the ethanol vapor chamber procedure) can usurp normal learning processes in the striatum that are engaged in automatization of skills and habit formation to have significant impact on the subsequent control of reward- guided behavior. Accordingly, three specific aims are proposed: 1) To determine the effects of prior ethanol exposure on striatum-dependent learning and behavior. 2) To determine the effects of prior ethanol exposure on striatal neural activity in awake behaving mice during instrumental learning. 3) To determine the effects of prior ethanol exposure on striatal synaptic transmission ex vivo using whole-cell patch clamp recording. This proposal employs an innovative and integrative approach in studying ethanol actions on the brain, by combining in vivo and ex vivo electrophysiological methods with powerful assays from the study of instrumental learning. Results from the proposed experiments will help us understand the neuroadaptive mechanisms in the cortico-striatal circuits that mediate the acquisition and control of goal-directed actions and habit formation. Such mechanisms can provide novel targets for the treatment of alcohol addiction.